Remove querystring value on page refresh

Question

I am redirecting to a different page with Querystring, say

header('location:abc.php?var=1');

I am able to display a message on the redirected page with the help of querystring value by using the following code, say

if (isset ($_GET['var']))
{

    if ($_GET['var']==1) 
    {
        echo 'Done';
    }
}

But my problem is that the message keeps on displaying even on refreshing the page. Thus I want that the message should get removed on page refresh i.e. the value or the querystring should not exist in the url on refresh.

Thanks in advance.

Answer 1

You cannot "remove a query parameter on refresh". "Refresh" means the browser requests the same URL again, there's no specific event that is triggered on a refresh that would let you distinguish it from a regular page request.

Therefore, the only option to get rid of the query parameter is to redirect to a different URL after the message has been displayed. Say, using Javascript you redirect to a different page after 10 seconds or so. This significantly changes the user experience though and doesn't really solve the problem.

Option two is to save the message in a server-side session and display it once. E.g., something like:

if (isset($_SESSION['message'])) {
    echo $_SESSION['message'];
    unset($_SESSION['message']);
}

This can cause confusion with parallel requests though, but is mostly negligible.

Option three would be a combination of both: you save the message in the session with some unique token, then pass that token in the URL, then display the message once. E.g.:

if (isset($_GET['message'], $_SESSION['messages'][$_GET['message']])) {
    echo $_SESSION['messages'][$_GET['message']];
    unset($_SESSION['messages'][$_GET['message']]);
}

Answer 2

Better use a session instead

Assign the value to a session var

$_SESSION['whatever'] = 1;

On the next page, use it and later unset it

if(isset($_SESSION['whatever']) && $_SESSION['whatever'] == 1) {
  //Do whatever you want to do here

  unset($_SESSION['whatever']); //And at the end you can unset the var
}

This will be a safer alternative as it will save you from sanitizing the get value and also the value will be hidden from the users

Answer 3

There's an elegant JavaScript solution. If the browser supports history.replaceState (http://caniuse.com/#feat=history) you can simply call window.history.replaceState(Object, Title, URL) and replace the current entry in the browser history with a clean URL. The querystring will no longer be used on either refresh or back/previous buttons.